A rubber material which has rubber resilience and anisotropy of strength has been recently desired elements for such as sports equipment hoses and the like.
In order to impart anisotropy strength to a rubber article, it is known that fibers (e.g. short fibers) or fillers (e.g. silica and mica) are mixed with the rubber composition under a shearing force and oriented in a certain direction. In this process, however, since the fibers have poor miscibility with rubber, it takes long time to disperse the fibers in the rubber composition. Thus the rubber composition thus obtained often gives rise to problems in dispersibility and retention of fiber form (e.g. breaking or bending of the fibers). If the fillers are formulated for anisotropy strength, a large amount of the fillers must be formulated into the rubber composition in order to impart thereto sufficient orientation. This large amount of fillers adversely affects the physical properties (e.g. tensile strength, wear resistance and compression set) of the resulting rubber.